An innovation that opens horizons for greenhouse gases' remote monitoring

Brazilian researchers design a tiny spectrometer for integration into drones, smartphones and other devices to detect chemical compounds and remotely monitor greenhouse gases. Credit: FAPESP
 https://phys.org/news/2018-05-horizons-greenhouse-gases-remote.html#jCp

Fourier-transform infrared (FTIR) spectrometers, among the most frequently used research tools to identify and analyze chemicals, are too large to be used in the field to detect compounds.

Several attempts have been made to develop miniaturized FTIR spectrometers for integration into drones to monitor greenhouse gases remotely, or for integration into smartphones and other devices. However, current miniaturized devices are costly to produce.

Scientists at the University of Campinas's Device Research Laboratory (LPD-UNICAMP) in Brazil, collaborating with colleagues at the University of California San Diego in the United States, have overcome these constraints by developing an FTIR spectrometer based on silicon photonics, the technology currently used to produce chips for computers, smartphones and other electronic devices.

The study was led by Mário César Mendes Machado de Souza and a research internship abroad, and published in Nature Communications. Souza is the article's lead author.

"Silicon photonics offers a platform for the fabrication of affordable high-performance miniaturized spectrometers," he said.

According to Souza, FTIR spectroscopy identifies chemicals using an infrared light source to measure absorption. A sample is exposed to different wavelengths of infrared light, and the spectrometer measures which wavelengths are absorbed. The computer takes these raw absorption data and conducts a mathematical process known as the Fourier transform to generate an absorbance pattern or spectrum, which is compared to a library of spectra for chemical compounds to find a match.

Projects have attempted in recent years to develop an FTIR spectrometer based on integrated photonics, which uses light especially in the infrared spectrum, but progress has been minimal owing to several technical challenges, Souza explained. One of these challenges is the highly dispersive profile of silicon waveguides, meaning that each wavelength travels at a different speed in this material and hence has a different refractive index.

The refractive indices of optical waveguides in silicon can be "tuned" by means of the thermo-optical effect, which involves passing a current over the waveguide in order to heat it. Because the device has to be operated at high temperatures in order to achieve high resolution, this technique becomes nonlinear in the sense that changes in temperature correlate with disproportionate changes in the refractive index.

"In practice, what happens when a thermo-optical effect is applied to a silicon-based infrared spectrometer with integrated photonics is that the Fourier transform mathematical operations used to convert the radiation spectrum data collected produce completely wrong results," Souza explained.

The researchers overcame these challenges by creating a laser calibration method to quantify and correct the distortions caused by silicon waveguide dispersion and non-linearity. As a proof of concept, they developed a 1 mm² FTIR spectrometer chip based on standard silicon photonics fabrication procedures.

The chip was tested in the laboratory, producing a broadband spectrum with a resolution of 0.38 terahertz (THz), which is comparable with the resolution of commercially available portable spectrometers that operate in the same wavelength range, according to the researchers. "The device we developed is far from optimized but still achieves resolutions comparable with those of the portable free-space optics-based spectrometers available in the market today," Souza said.

The researchers now plan to engineer a device that is totally functional and integrated with photodetectors, light sources and optical fibers. "Our goal is to integrate the light source and the spectrometer's detector into the same platform," Souza said.

OT- LUNA Blog-New Component Analyzer for Silicon Photonics and PICs

http://lunainc.com/component-analyzer-silicon-photonics-pics/


At the OFC 2018 in San Diego recently, we unveiled the newest member of Luna’s family of high-performance test equipment for the lightwave industry.  The LCA 500 Lightwave Component Analyzer combines industry-leading resolution and sensitivity with high speed and simplified setup to deliver a component characterization solution that extends beyond the R&D lab and onto the production floor.

High Fidelity IL, RL and PDL

The rapidly advancing technology of modern silicon photonics and photonic integrated circuits (PICs) is driving the need for higher precision measurement solutions that are able to accurately characterize miniaturized wide bandwidth components.  The LCA 500 delivers highly accurate loss measurements, including insertion loss (IL), return loss (RL) and polarization dependent loss (PDL), which is critical for modern integrated photonic components.

Simplified Setup

Like Luna’s other lightwave test products, the LCA 500 simplifies your test setup and configuration, incorporating a built-in precision tunable laser source (TLS) and able to measure components in both transmission and reflection. The LCA 500 also reduces test time with fast scans of the complete C and L band, or O band, I less than 3 seconds.  Therefore, your test setup and execution is streamlined without the need for an external TLS or manual reconnections. 

Learn more about the LCA 500 Lightwave Component Analyzer.

OT Luna Blog-Join us at OFC!

http://lunainc.com/join-ofc/

March 2, 2018

As always, we’re going to be exhibiting at OFC again this year and we hope to see you there!  Visit us in booth #3539!

Whether you are developing the next generation of Silicon Photonics or looking to improve the quality and reliability of fiber networks and components, our revolutionary test and measurement technology will enhance your research, improve your designs and help bring your photonic products to market faster. We invite you to stop by our booth at OFC in San Diego, CA beginning March 13^th to see active working demonstrations of the industry’s only Optical Vector Analyzer (OVA) and “Zero Dead Zone” OBR reflectometers:

• High speed all parameter analysis with the OVA 5000
• Unprecedented visibility into optical components and short networks with the OBR 4600
• High speed, high resolution analysis of cables and connectors with the OBR 5T-50

Additionally, we will be previewing our latest development, the LCA 500 Lightwave Component Analyzer, which is ideal for the characterization of modern silicon photonics and phonic integrated circuits.

Click here to register for your free pass today! 

March 13-15, 2018
San Diego Convention Center | San Diego, California
Booth #:  3539

OT LUNA BLOG-Characterizing devices with the OVA 5000 – Accelerating R&D in Silicon Photonics

https://lunainc.com/characterizing-devices-ova-5000-accelerating-rd-silicon-photonics/

June 10, 2016

The OVA 5000 – Speeding Development of Silicon Photonics Research

The Luna OVA 5000 has many features and capabilities that can dramatically reduce laboratory test time in the pursuit of Silicon Photonics research. One of the more significant, yet often overlooked, capabilities is the OVA’s ability to measure a device’s linear transfer function and then derive a wide variety of industry standard parameters with a single laser sweep. This mathematical model is in the form of the Jones Matrix, which is a 2 x 2 matrix representing the complete mathematical description of an optical device.  All linear device parameters such as insertion loss, group delay, polarization dependent loss, and polarization mode dispersion, as well as more subtle effects such as a second order PMD that may exist in the device are easily computed from the Jones matrix. The device characterization performed by the OVA encapsulates all optical properties in a single compact matrix that is fundamentally rigorous, making it an ideal tool for modeling and understanding fiber optic systems. With the OVA 5000, scientists and engineers test a component once and then analyze its performance a thousand different ways.  Conventional test methods would require several iterations of testing, each with its own time consuming set up. A single test using conventional test methods provide a single answer to a very specific question; the OVA 5000, by mathematically modeling the device, provides the answer to the original question, and every question thereafter.   

Device Modeling and Simulation

Simulation and modeling tools are an integral part of the design process for electronic integrated circuits and will also be essential in the design and development of photonic integrated circuits on a silicon platform.  By effectively modeling the behavior of these devices, engineers can ensure that costly prototypes perform as expected.  The unique ability of the OVA 5000 to mathematically model a device is perfectly complementary for these simulation tools. The model generated by the OVA5000 can be used as input to modeling and simulation tool kits.  OptSim, a modeling program from Rsoft, has an interface to use the OVA 5000’s Jones matrix as input for its simulation. 

In addition, Luna’s Polarization Analysis Software (PAS) can analyze the device Jones matrix to find the principle polarization response states of the device, based on either device loss or group delay. Using the Jones Matrix, PAS can also simulate the device response toANY pure polarization state.

Silicon Photonics and the AIM initiative

Effective simulation and modeling will be a critical to advance Silicon Photonics into mass production.  In fact, developing a set of integrated design tools for photonic and combined electronic-photonic components is one of the four main objectives of the AIM initiative.  AIM is the American Institute for Manufacturing Integrated Photonics and is a public/private consortium whose charter is to remove barriers for the adoption of integrated photonics into industry. 

Luna Blog-You Can’t Fix What You Can’t See – Luna’s OBR 4600 Enables Unprecedented Visibility into Silicon Photonics Designs

http://lunainc.com/lunas-obr-4600-silicon-photonics-cant-fix-cant/

At the recent OFC show in Anaheim California, Luna Innovations showcased how their OBR 4600 reflectometer helps advance research in the field of Silicon Photonics.  Working with the Blumenthal and Bowers Optoelectronics Research Groups at the University of California Santa Barbara, Luna Innovations demonstrated how the OBR 4600 can be used to determine the distributed loss across a 1 meter spiral delay line fabricated on a silicon platform and occupying a mere 1 cm² footprint.

A One Meter Spiral Delay Line Fabricated on a Silicon Platform

The OBR 4600 was optically coupled to the waveguide using a single mode glass fiber connectorized at one end for use with the OBR 4600 front panel connector.  The OBR 4600, with its noise floor of -130 dB, dynamic range of 70 dB and 10 micron spatial resolution, was able to see a remarkable level of detail inside the silicon waveguide.  Not only could the OBR 4600 determine a total distributed loss across the device of 30 dB per meter, but was also able to capture the individual loss events as the horizontal waveguide crossed each ring of the spiral delay, some with spacing of only 50 microns.

Figures 1 thru 3 below demonstrate the value of the OBR 4600 in windowing deep inside a Silicon Photonics device to characterize the distributed loss across the photonic circuit.  

You can’t fix what you can’t see. While Silicon Photonics devices are an extreme example of packing a large amount of functionality into a very small package, the reality is that higher data rates are driving data center component manufactures to reduce the size of passive optical components.  The OBR 4600 – it can see inside your chip and help find problems early in your design cycle.    

To learn more about how Luna’s OBR 4600 can help accelerate your Silicon Photonics R&D  click here.

To talk to someone call 540.961.5190 or to ask a question or request a quote click here solutions@lunainc.c

Luna Innovations- to participate at OFC 2016

We’ll be at OFC 2016

March 9, 2016

http://lunainc.com/well-ofc-2016/

As always, we’re going to be exhibiting at OFC again this year and we hope to see you there!

Visit us at booth #1341

We will be demonstrating our optical technologies, including our Component Analyzers, Reflectometers, and Tunable Lasers.

Why you should stop by…

Our solutions offer substantial cost and time savings in development, production and maintenance; providing the most comprehensive, sensitive, and accurate testing available.

We’ll be demonstrating the following revolutionary products:

• OVA 5000
  • The standard of test for Silicon Photonics
• OBR 4600
  • Unprecedented visibility into integrated optics
  • Network visibility with sub-mm resolution
• OBR 5T-50
  • High speed, high resolution RL for cables, connectors, and components

Beyond that, you’ve got to see our innovative Sensing solution

As we did last year, we will be showing off our breakthrough ODiSI platform, which is our distributed sensing solution for Strain & Temperature measurement that is more cost-effective, easier-to-install, and more accurate than anything else on the market today!

And right next door, our Picometrix division will be exhibiting in booth #1441

Come see high speed optical components used by the telecommunications market for transmission and test & measurement

• Fiber-to-the-Home/Premise (FTTx)
  • 5G APD, 10G APD, 25G APD
• Long-Haul/Metro market
  • ≥100G coherent receivers

Don’t forget to stop by the Luna booth #1341 & #1441

It’s going to be a great show and we hope to see you there!

OFC Conference 2016

France's LETI touts industry connections

Satellite meeting adjacent to Photonics West venue talks silicon photonics, neurophotonics, molecular sensors, and terahertz imaging. http://optics.org/news/7/2/26

LETI cleanroom by Ford Burkhart Researchers connected with LETI, the French technology research institute, told their story to SPIE Photonics West attendees in a satellite session, detailing how their projects are helping bridge the gap between research and industry – a recurring theme at the wider event. Ludovic Poupinet, head of LETI’s optics and photonics division with its ten labs and 300 research staff, summed up the message saying LETI’s biggest strength is flexibility. “That’s what we do,” he said, “in many kinds of partnerships with universities, with diversity of process, and integration of heterogeneous nano devices.” “We can address users with large sets of technology, not just one idea,” he said. “We are always welcoming new problems.” HP source With a nod to the Americans in the audience at San Francisco’s St. Regis Hotel, across the street from the Moscone Center, Poupinet recalled how HP Labs approached LETI a few years ago seeking help in silicon photonics. “They could they could not find in all the world a place with people ready to address their specifications.” A small collaboration is underway, he said, adding, “We are extending it now, fabricating components for them.” Other ongoing work on silicon photonics at LETI includes the four-year “PLAT4M” European project, which involves IMEC and ST Microelectronics, among others. LETI stands for “Laboratoire d’electronique et de technologie de l’information.” Hughes J. Metras, LETI’s Pasadena-based vice president for strategic partnerships, said the organization, founded in 1967 to work in electronics, added the optics division in 1980. The research center – a division of the French Alternative Energies and Atomic Energy Commission (CEA) – plays a similar role to the Fraunhofer organization in Germany and IMEC in Belgium, and has 1,700 researchers in all. Neurophotonics Based in Grenoble, LETI is best known for micro- and nano-electronics development, with Poupinet pointing to its work on image sensors for smart phones as one of its most significant accomplishments. LETI also has a strong record in military, space, and X-ray applications, and typically obtains 60-70 new patents per year. “We are able to cover the full spectrum of research activities,” Poupinet said, with an emphasis on integration, miniaturization, and industrial connections. “We are an ecosystem of industrial partners for component manufacturing,” he added. In San Francisco Michael Roukes, the Robert M. Abbey Professor of Physics at Caltech in Pasadena, California, described his “massively parallel interrogation” project with LETI, using photonic nanoprobes to study brain activity - a field he refers to as “integrated neurophotonics”. He said the neuroprobes are able to measure via 1024 channels. And although, in his words, that still represents “not even a drop in the bucket” when measured against the 100 billion neurons in our brains, Roukes expects the number to rise to 100,000 channels within four years. That progress should be accompanied with the ability to “massively multiplex” the neural probes. “There are great things to come in this field, and they will have a great impact in brain science,” he said. Molecular sensors and imaging Sergio Nicoletti, of LETI’s optics and photonics department, described his group’s research on detecting chemicals at the “sub-parts-per-billion” level. The spectral sensors are able to measure “clear and intense fingerprints of molecules” in the mid-infrared region, and in turn monitor gas emissions for public health. Nicoletti’s lab is also working on lab-on-a-chip prototypes of sensors based around tunable laser diode spectroscopy. Using a monolithic array of quantum cascade lasers (QCLs), LETI researchers have developed a mid-infrared photonic integrated circuit (MIR-PIC) platform, which can switch between each QCL wavelength. LETI’s QCL-focused spin-out company mirSense was among those in the French pavilion at the nearby Photonics West exhibition, showcasing its compact, portable and sensitive spectroscopic devices. Francois Simoens, who studies imaging sensors, described LETI’s work with devices that provide information useful in machine learning. LETI’s projects have ranged from high-end applications in space and security to consumer products – including hyperspectral and terahertz technologies. Recent demonstrations have included a state-of-the-art uncooled terahertz video imaging camera, which is based around a new (and patented) antenna-coupled bolometer array. “We cover the whole value chain,” Simoens said, “from optics, to the system level.” He also recalled the role of LETI in design and fabrication of a much larger bolometer-based camera for the European Space Agency’s Herschel space telescope, launched in 2009 to observe in the far-infrared spectral region. Micro-LEDs Ivan-Christophe Robin, LETI’s strategic marketing manager for photonic devices, told of his research on “micro-LED” arrays for smart lighting applications. Like the mirSense QCLs, the company’s gallium nitride devices are the result of long-standing compound semiconductor material expertise developed at LETI, integrated with the advantages provided by more conventional silicon semiconductor platforms. The “iLED” matrix technology, showed off with a demonstration at January’s Consumer Electronics Show in Las Vegas, could wind up being used in automotive headlamps, tiny wearable screens, and head-up displays.

Japanese Team Achieves 8.8THz Laser Diode Tuning Range

Quantum dot and silicon-based laser could exploit near infra red bands

http://www.compoundsemiconductor.net/article/97210-japanese-team-achieves-8.8thz-laser-diode-tuning-range.html

Researchers at Tohoku University and the National Institute of Information and Communications Technology (NICT) in Japan, have developed a novel ultra-compact heterogeneous wavelength tunable laser diode. The heterogeneous laser diode was realised through a combination of silicon photonics and quantum-dot (QD) technology, and demonstrates a wide-range tuning-operation.

The researchers presented their work at a Conference on Lasers and Electro-Optics (CLEO) in San Jose, California, on May 13. The related paper was also published inApplied Physics Express.

Recent high-capacity optical transmission systems are based on wavelength-division multiplexing (WDM) systems with dense frequency channels. The frequency channels in C-band (conventional band: 1530- 1565nm) are overcrowded and the frequency use efficiency is saturated in such WDM systems. On the other hand, extensive and unexploited frequency resources are buried in near-infra-red wavelengths (1000-1300nm). 

Additionally, photonic devices are required to have smaller footprints and lower power consumption in short-reach data transmission. The compact and low power consumption wavelength tunable laser diode is a key device to tap the undeveloped frequency bands for higher capacity data transmission systems, according to the researchers.

The heterogeneous wavelength tunable laser diode, consisting of the QD and the silicon photonics, is a promising candidate to realise such a compact and broad-band light source. This is because the QD has large optical gains of around 1000-1300nm wavelength, and silicon photonics provide a promising platform for highly integrated photonics devices - so a novel wavelength-tunable laser diode, combining QD and silicon photonics technologies, was proposed.

The cooperative research group led by Tomohiro Kita and Naokatsu Yamamoto demonstrated a wide range tuning operation of around 1250nm wavelength with an ultra-small device footprint. The obtained frequency tuning-range of 8.8THz is said to be a world record for the category of QD and silicon photonics heterogeneous wavelength tunable laser diodes. 

It is expected that the fusing of the QD technology and silicon photonics will provide a breakthrough for the development of an effective and compact light source.

This research was partially supported by the Strategic Information and Communications R&D Promotion Program (SCOPE) of Japan's Ministry of Internal Affairs and Communications.

'Ultra-compact wavelength-tunable quantum-dot laser with silicon-photonics double ring filter' by Tomohiro Kita et al; Appl. Phys. Express 8 062701

Abstract-Voltage-switchable photocurrents in single-walled carbon nanotube–silicon junctions for analog and digital optoelectronics

Young Lae Kim, Hyun Young Jung, Sora Park, Bo Li, Fangze Liu, Ji Hao, Young-Kyun Kwon,Yung Joon Jung ,Swastik Kar

http://www.nature.com/nphoton/journal/vaop/ncurrent/full/nphoton.2014.1.html

Recent progress in silicon photonics has dramatically advanced the possible realization of heterogeneous logic circuits. A variety of Boolean optoelectronic circuits have been proposed. In this context, experimental investigation of logic operations with both optical and electrical inputs in chip-integrable devices is highly desirable. Here, we present a new kind of photodiode-based logic device using scalable heterojunctions of carbon nanotubes and silicon, the output currents of which can be manipulated completely by both optical and electrical inputs. This provides a novel platform for heterogeneous optoelectronic logic elements with voltage-switchable photocurrent responsivity of >1 A W⁻¹, photovoltage responsivity of >1 × 10⁵ V W⁻¹, electrical on/off ratios of >1 × 10⁵ and optical on/off ratios of >1 × 10⁴. To demonstrate their scalability, we fabricated a large array of photoactive elements on a centimetre-scale wafer. We also present bidirectional phototransistors and novel clock-triggerable logic elements such as a mixed optoelectronic AND gate, a 2-bit optoelectronic ADDER/OR gate and a 4-bit optoelectronic digital-to-analog converter.